1. Field of the Invention
The present invention relates to a substrate processing apparatus and substrate processing method to apply a process such as application of a resist agent, exposure and development on the surface of a substrate such as a semiconductor wafer or liquid crystal display substrate.
2. Description of the Background Art
The process of forming a circuit pattern on the surface of semiconductor wafers, liquid crystal display substrates (LCD substrate) and the like includes a wide range of steps. In a substrate processing apparatus, a dedicated processing unit is provided for each step. The system is constituted by a combination of a plurality of these units. The substrate to be processed is moved between each unit by conveyer means. For example, a resist film of a predetermined pattern is formed on a substrate processed by a substrate processing apparatus.
The structure and operation of a conventional substrate processing apparatus shown in FIG. 16 will be described hereinafter. The substrate processing apparatus includes, in the order from the carry-in side of a substrate towards the back side, a cassette station 1A, a processing block 1B, an interface unit 1C and an exposure device 1D.
A wafer cassette C in which a wafer W is stored is carried into the substrate processing apparatus from cassette station 1A. A wafer deliver means not shown is provided between cassette station 1A and processing block 1B. Wafer W is transferred from cassette station 1A to processing block 1B by the wafer deliver means.
Referring to processing block 1B, a rack unit 12 is disposed at the front side, left side and rear side about main conveyer means 10, viewed from the cassette station 1A side. An agent processing unit 13 is arranged at the right side. Main conveyer means 10 includes a main arm 11 that can move forward and backward, up and down, and rotatable in the horizontal direction. In each rack unit 12, a plurality of processing units such as a unit for a heating process and a unit for a cooling process are stacked in a plurality of stages. Agent processing unit 13 includes a unit for application, a unit for development, and the like.
Interface unit 1C functions to deliver wafer W between main conveyer means 10 and exposure device 1D.
Main conveyer means 10 will be described in detail here. Main conveyer means 10 includes a rotary table that can be rotated for a predetermined angle (xcex8), and a base elevation mechanism disposed on this rotary table. The base includes an arm 11 that can move forward and backward. Wafer W is held by arm 11. In the delivery of wafer W between respective units, the base with the forward and backward mechanism and elevation mechanism rotates at a predetermined angle on the rotary table in an integral manner.
Although not shown, the elevation mechanism of main conveyer means 10 includes a guide shaft that guides the upward and downward movement of arm 11. The frequent up and down movement of arm 11 along the guide shaft causes the surface of the guide shaft to be subjected to friction by arm 11. The guide shaft is a member that has the high possibility of producing particles among the members constituting main conveyer means 10. Therefore, during the rotation of main conveyer means 10, minute contaminants or particles generated by the guide shaft may float out to the atmosphere. The wiring for the power and control of the elevation mechanism of main conveyer means 10 must be arranged so as to withstand the rotary movement since the base thereof including the forward and backward mechanism and elevation mechanism is rotated on the rotary table integrally. There is a problem that the space for installment thereof is increased.
To overcome such problems, the inventor of the present application is studying the structure of the transportation means for wafer W such as that shown in FIG. 17. Referring to FIG. 17, a pair of elevation mechanisms 14 are provided so as to sandwich a shutter unit 16 of agent processing unit 15 stacked in a plurality of stages. A conveyer main unit 18 with arm 11 is supported by a support member 17. The pair of elevation mechanisms 14 include a guide shaft to guide the up and down movement of support member 17. Elevation mechanism 14 raises and lowers conveyer main unit 18 via supporting member 17.
Conveyer main unit 18 includes a rotation mechanism to rotate arm 11 by a predetermined angle (xcex8), and a forward and backward mechanism to move arm 11 forward and backward. Accordingly, wafer W held by arm 11 can be conveyed to another processing unit (a processing unit other than agent processing unit 15 in the drawing) located around conveyer main unit 18.
Since the rotation mechanism and elevation mechanism are provided separated from each other according to the above-described structure, the wiring arrangement is simplified.
However, the conveyer means of FIG. 17 has the pair of elevation mechanism 14 provided in the proximity of shutter unit 16 of agent processing unit 15. When shutter 16 opens at the time of delivery of wafer W, the wind flow generated by the elevation or forward or backward movement of conveyer main unit 18 will blow up the particles generated at elevation mechanism 14. There is a possibility that these floating particles will enter agent processing unit 15.
An object of the present invention is to provide a substrate processing apparatus and a substrate processing method that can prevent intrusion of particles generated in accordance with the operation of an elevation mechanism provided in the transportation means of a substrate into the processing unit.
According to an aspect of the present invention, a substrate processing apparatus includes a processing unit applying a process on a substrate carried into a processing vessel through a conveyer inlet, a conveyer base provided so as to face the conveyer inlet, and having an arm that can move forward and backward to deliver a substrate with respect to the processing unit through the conveyer inlet, a casing having an opening elongated in the vertical direction, a support member extending inside and outside the casing through the opening to support the conveyer base outside the casing, an elevation mechanism provided in the casing to move the support member upward and downward, and discharge means for discharging gas in the casing.
According to such a structure, the elevation mechanism that has the high possibility of generating particles among the members associated with the transportation of a substrate is enclosed by a casing. Also, discharge means is provided in the casing. Therefore, particles generated at the elevation mechanism at the time of the up and down movement of the conveyer base can be prevented from moving towards the conveyer inlet of the agent processing unit.
In a preferable embodiment, the casing includes a first chamber and a second chamber divided by a partition wall having a vent hole. The first chamber includes the opening through which the support member passes. The elevation mechanism is disposed in the first chamber. The discharge means is disposed in the second chamber. Accordingly, the particles generated in the first chamber can be attracted to the second chamber through the vent hole. Then, the particles can further be discharged outside.
In the above case, the partition wall is a perpendicular wall extending, for example, in the vertical direction. The vent hole is a vertical slit of a length corresponding to the distance of the up and down movement of the support member. Accordingly, particles can be discharged from the entire site that readily generates particles such as the guide shaft included in the elevation mechanism. This is particularly advantageous when processing units are stacked in a plurality of stages so that the elevation frequency of the conveyer base is high. The casing may be provided in a pair with the conveyer inlet of the processing unit therebetween.
In an embodiment of the present invention, the discharge means includes a discharge fan arranged in the casing. In this case, a plurality of discharge fans can be arranged in the vertical direction in the casing.
In the case where the casing is divided into the above-described first and second chambers, the plurality of discharge fans are preferably arranged in the vertical direction in the second chamber. The discharge fan is arranged in a direction rotated in a horizontal plane, for example. In this case, the plurality of discharge fans may be arranged so that the discharge fans located at the upper portion guide the gas upwards and the discharge fans located at the lower portion guide the gas downwards. By such a structure, the length of the discharge path is reduced. Therefore, a fan of low power can be used.
Preferably, the conveyer base includes a rotation mechanism to rotate the arm by a predetermined angle in a horizontal plane. As described above, the casing with the elevation mechanism and the discharge means located inside is provided in a pair with the convey inlet therebetween in a preferable embodiment. By such a structure, the elevation mechanism is separated from the rotation mechanism, so that the elevation mechanism will not be rotated. Therefore, the arrangement of the wiring for the power and control of the elevation mechanism can be effected easier.
Typically, the processing unit includes a plurality of units arranged in a stacked manner in a plurality of stages. The processing unit includes a shutter to open/close the conveyer inlet, for example.
In another embodiment of the present invention, the casing includes a wall facing the conveyer inlet, and a wall not facing the conveyer inlet. The opening is formed at the wall that does not face the conveyer inlet. By such a structure, particles, even if generated in the casing, will not easily enter through the conveyer inlet since the opening is located distant from the conveyer inlet.
According to a further embodiment of the present invention, the support member includes a vent path to guide the particles generated in the conveyer base to the casing. Particles generated at, for example, the rotation mechanism of the arm are attracted into the casing via the vent path of the support member to be discharged outside. The support member has, for example, a hollow configuration.
According to another aspect of the present invention, a substrate processing apparatus includes a processing unit applying a process on a substrate carried into a processing vessel through a substrate conveyer inlet, a conveyer base provided to face the conveyer inlet, and having an arm that can move forward and backward to deliver the substrate with respect to the processing unit through the conveyer inlet, a casing having an opening elongated in the vertical direction, a support member extending inside and outside the casing through the opening to support the conveyer base outside the casing, an elevation mechanism provided in the casing to move the support member in an up and down direction, and gas supply means producing a gas flow at a position facing the conveyer inlet to prevent particles from entering the processing unit through the conveyer inlet.
According to such a structure, purge gas, for example, can be supplied towards the conveyer inlet of the processing unit to form a gas curtain. The gas curtain functions as a barrier to the atmosphere outside the substrate conveyer inlet. Therefore, contamination when the substrate is carried into the processing unit can be prevented. Also, intrusion of particles into the processing unit through the conveyer inlet can be prevented.
The processing unit includes a shutter to open/close the conveyer inlet, for example. The gas supply means supplies gas when the shutter opens for the delivery of a substrate between the arm and the processing unit. The gas supply means includes, for example, a gas blow outlet at left and right positions with the conveyer inlet therebetween. Gas is blown out from the left and right gas blow outlets in a direction towards each other.
In an embodiment, the processing unit includes a plurality of units stacked in a plurality of stages. The gas supply means includes a gas supply tube extending from a position corresponding to the bottommost unit to the position corresponding to the topmost unit. The gas supply tube includes a gas eject hole at a position corresponding to the conveyer inlet of each unit.
The processing unit includes, for example, a plurality of units stacked in a plurality of stages. The gas supply means is provided independent of each unit. In this case, each unit preferably includes a shutter that opens/closes the conveyer inlet. Each gas supply means supplies gas only when the shutter of the corresponding unit is open.
The casing includes, for example, a wall facing the conveyer inlet, and a wall not facing the conveyer inlet. The opening is formed at the wall that does not face the conveyer inlet.
A substrate processing method of the present invention employs a substrate processing apparatus including a processing unit applying a process on a substrate carried into a processing vessel via a substrate conveyer inlet, a conveyer base provided to face the conveyer inlet, and having an arm that can move forward and backward to deliver a substrate with respect to the processing unit through the conveyer inlet, a casing having an opening elongated in the vertical direction, a support member extending inside and outside the casing through the opening to support the conveyer base outside the casing, and an elevation mechanism provided in the casing to move the support member upward and downward. In one aspect, the substrate processing method includes the steps of delivering a substrate between the conveyer base and the processing unit by the arm passing through the conveyer inlet, attracting the gas in the proximity of the opening of the casing into the casing, and discharging the gas in the casing.
According to another aspect, the substrate processing method includes the steps of delivering a substrate between the conveyer base and the processing unit by the arm passing through the conveyer inlet, and supplying gas to a position facing the conveyer inlet to produce a flow of gas preventing intrusion of particles into the processing unit through the conveyer inlet.